Create a handle and open a connection to the preferred audio interface
#include <sys/asoundlib.h> int snd_pcm_open_preferred( snd_pcm_t **handle, int *rcard, int *rdevice, int mode );
You can OR this flag with any of the above:
You can change the blocking setup later by calling snd_pcm_nonblock_mode().
The snd_pcm_open_preferred() function is an extension to the snd_pcm_open() function that attempts to open the user-selected default (or preferred) device for the system.
In a system where more than one PCM device exists, you can set a preference for one of these devices. This function attempts to open that device and return a PCM handle to it. The function returns the card and device numbers if the rcard and rdevice arguments aren't NULL.
For information on how io-audio sets the preferred device, see Preferred device selection in the io-audio chapter of the QNX Neutrino Utilities Reference.
Zero on success, or a negative value on error.
See the example in Opening your PCM device in the Playing and Capturing Audio Data chapter.
QNX Neutrino
Safety: | |
---|---|
Cancellation point | No |
Interrupt handler | No |
Signal handler | Yes |
Thread | Read the Caveats |
This function is not thread safe if handle (snd_pcm_t) is used across multiple threads.
Successfully opening a PCM channel doesn't guarantee that there are enough audio resources free to handle your application. Audio resources (e.g. subchannels) are allocated when you configure the channel by calling snd_pcm_channel_params() or snd_pcm_plugin_params() .